June 24, 1898.] 



SCIENCE. 



853 



■could be reached by the use of liquid air. 

 A much larger apparatus of the same type 

 was then constructed, in which the liquid 

 air plant was combined in its circuits and 

 arrangements for the liquefaction of hydro- 

 gen. The construction of this apparatus 

 consumed a year, and many months were 

 occupied in preliminary trials and tests. On 

 May 10th hydrogen was liquefied by allow- 

 ing the gas, cooled to —205°, and under a 

 pressure of 180 atmospheres, to escape con- 

 tinuously, at the rate of ten to fifteen cubic 

 feet per minute, from the nozzle of a coil of 

 pipe in a double silvered vacuum vessel 

 of special construction, surrounded by a 

 space kept below — 200°. Liquid hydrogen 

 commenced to drop from this vacuum ves- 

 sel into another doubly isolated by being 

 surrounded by a third. 20 cc. liquid hy- 

 drogen were obtained before the hydrogen 

 jet froze up from the solidification of the air 

 in the pipes. Liquid hydrogen is clear and 

 colorless, showing no absorption spectrum, 

 and the meniscus is as well defined as in 

 the case of liquid air. It has a relatively 

 high refractive index and dispersion, and its 

 density appears to be in excess of the theo- 

 retical value 0.18 to 0.12, deduced from its 

 atomic volume in organic compounds, and 

 the limiting density found by Amagat for 

 hydrogen gas under infinite compression. 

 Dewar's experiments have given a density 

 of 0.62 for hydrogen condensed by pallad- 

 ium, and this may not be far from the value 

 for the liquid. No arrangements were at 

 hand to determine the boiling point of hy- 

 drogen, but it must be excessively low, for 

 a long piece of glass tubing sealed at the 

 lower end and cooled by immersion in liquid 

 hydrogen immediately filled with solid air 

 where it was cooled. A tube of helium from 

 the Bath gas was placed in liquid hydrogen, 

 -and a distinct liquid was seen to condense, 

 thus showing that there cannot be any great 

 ■difl^erenoe in the boiling points of hydrogen 

 and helium. All known gases have now 



been condensed to liquids which can be 

 manipulated at their boiling points under 

 atmospheric pressure in suitably arranged 

 vacuum vessels. With hydrogen as a cool- 

 ing agent, it will be possible to get within 

 20° or 30° degrees of the absolute zero, and 

 its use will open up an entirely new field of 

 scientific inquiry. 



In seconding a vote of thanks to Professor 

 Dewar, moved by Sir William Crookes, Dr. 

 Armstrong called attention to the fact that 

 in the earlier days of the Chemical Society 

 much attention had been given to the dis- 

 cussion of the properties of hj'drogen, and 

 the view that it possessed metallic proper- 

 ties had been strongly advocated. This was 

 strongly supported by Graham's investiga- 

 tions of hj'drogenized palladium, or, hj'dro- 

 genium, as Graham called it, condensed on 

 palladium. Dr. Armstrong ventured to 

 think, however, that the subject had been 

 too much regarded from the inorganic side, 

 and that when the evidence to be derived 

 from organic chemistry is taken into ac- 

 count it is more probable that hydrogen will 

 be found to resemble the petroleum hydro- 

 carbons rather than the metals. In reply 

 to a query from Dr. Armstrong, Professor 

 Dewar said that, since argon solidifies when 

 cooled in liquid air, his experiment with 

 helium shows that the gas (helium) from 

 the Bath well does not contain argon, and, 

 unless possibly hydrogen is present in small 

 quantity, the helium from the well was pure. 



According to chemical literature the dark 

 precipitate obtained by reducing bismuth 

 solution with alkaline stannous chlorid is 

 the monoxid, BiO. This oxid is also sup- 

 posedly obtained in the fusion of the metal. 

 L. Vanino and F. Treuberb, of Munich, 

 publish in the Berichte an investigation 

 of this compound, and show that in the 

 former case the precipitate is metallic bis- 

 muth and in the latter the compound is a 

 mixture of the metal with the ordinary oxid 



